Electric furnace.



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No. 713.923; Patented Nov. la, 1902.

A. A. SHADE. vELECTRIC FUBNAGE.

Applicaton led Dec. 2 8, 1901.) (No Model.) 4 Sheets-Sheet 2.

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UNITED STATES PATENT OFFICE.

ALBERT A. SHADE, OF CHICAGO, ILLINOIS, ASSIGNOR OF ONE-HALF TOEUGENE'HOWARD MOORE, OF CHICAGO, ILLINOIS.

ELECTRIC FU RNACE.

SPECIFICATION forming part of Letters Patent No. 713,923, dated November18, 1902. Application filed December 28,1901. Serial Ilo. 87,536. (Nomodel.)

T0 all U17/1,0111, it may concern.-

Beit known that LALBERT A.SHADE,of Chicago, in the county of Cook andState of Illinois, have invented certain new and useful Improvements inElectric Furnaces; and I do hereby declare that the following is a full,clear, and exact description thereof, reference being had to theaccompanying drawings, and to the letters of reference marked thereon,which form a part of this specification.

This invention relates to improvements in velectrical furnaces forsmelting or reducing ores and other fusible substances; and theinvention consists inthe matters hereinafter set forth, and moreparticularly pointed out in the appended claims.

In the drawings, Figure l is a side elevation of a furnace embodying myimprovements. Fig. 2 is a vertical section taken on line 2 2 of Fig. l.Fig. 3 is a vertical section of said furnace in a plane at right anglesto the plane of Fig. 2. Fig. 4 is a horizontal section taken on line 4 4of Fig. 3. Fig. 5 is an axial section, broken away, of one of the carbonelectrodes used in said furnace, showing applied thereto a metal collarby which the circuit-wire is connected with said electrode. Fig. 6 is aview, partly in elevation and partly in section, of two adjacentelectrodes, showing the manner of connecting the same. Fig. 7 is a plansection, on an enlarged scale, of the outer end of one of the carbonsand the devices for thrusting the same into the furnace. Fig. 8 is across-section taken on line 8 S of Fig. 7.

The furnace herein shown, in which my iinprovements are embodied, isprovided with an interior vertical passage, to the upper end of whichthe material to be smelted is fed in a granular form and provided at itslower end with a Crucible from which the molten material is withdrawn.Extending through the walls of the furnace and into said passage are aplurality of pairs of electrodes, between each pair of which in saidpassage is adapted to be formed an electric arc. Said pairs ofelectrodes are located. one above the other, so that the material passessuccessively through the arcs until it is deposited into the crucible,

from which the molten material is withdrawn as desired. Means areprovided beneath .each arc, excepting the lowermost one, for momentarilyretarding the progress of the material as it passes through the furnace,and means are provided for elongating or deflecting the arcs toward theplaces at which the material is momentarily retarded, whereby the heatof the arcs is more eectively applied to fuse or smelt the material. Thelowermost arc is located immediately above the open end of the crucible,and means are provided, as a magnet-,located below said crucible,todeflect said arc into the Crucible, so as to impinge upon the body ofthe molten material therein. The final fusing of the material takesplace in said crucible, and the molten material is withdrawn from saidCrucible to the molds or other place for the use of said moltenmaterial.

The foregoing general outline of the furnace herein shown has beenpresented for the purposeof facilitating an understanding of the detaildescription which follows and is not to be understood as limiting theinvention to the construction therein briefly set forth. As shown insaid drawings, the furnace consists, mainly, of a mass or bodyA, oflire-brick and of suitable form, which is provided with an interiorvertical passage A', into the upper end of which is fed the mate-v rialto be smelted through a pipe B, and C designates an open-topped crucibleembedded in the wall of the furnace at the lower end of said passage andin which the final fusion of the material takes place. Said body of thefu rnace is surrounded by a metallic shield A2, consisting of metalplates suitably secured together and conned by bands A3 A3. The spacebetween said shield A2 and the firebrick body of the furnace is filledwith a body of insulating material A4, such as mineral wool, asbestos,orthe like. Extending through the wall of the furnace and projecting intosaid passage A are a plurality of carbon electrodes arranged in pairs DD D2 D3 D1D5. The electrodes of each pair are disposed in axialalinement with respect to each other and are separated at their innerends, so that when a current is passed through the same an arc is formedin the passage between each pair of electrodes. The pairs of electrodesare arranged one above the other, so that the IOO y rial through thefurnace.

arcs formed between the same are all located in the path of the materialthrough the furnace, said material passing successively through the arcsof the series.

The walls of the passage A are so formed as to provide below the pairsof electrodes D D and D2 D3, respectively, oblique ledges A5 A5,whichproject into the path of the mate- The ledges A5 A6 project fromopposing side walls of the passage, and the walls of said passageopposite said ledges are provided with shallow recesses A7 A5, therebygiving to the passage a zigzag form. The pipe B is preferably arrangedwith its discharge end closely adjacent to the electrode D of theuppermost pair. The upper ledge A5 terminates short of the verticalplane of the inner end of the electrode D3, which is located below andextends through the wall of the furnace opposite to the said ledge A5,and the ledge A5 bears a like relation to the electrode D4 of thelowermost pair, which extends through the wall of the furnace oppositeto the said ledge A5. The material, therefore, passing from the pipe Bfirst strikes the ledge A5, which acts to momentarily retard or arrestthe progress of the same, and said material drops off the point of saidledge closely adjacent to but not in contact with the electrodes D5 andfalls upon the ledge A5, from whence it drops into the Crucible C,closely adjacent to but not in contact with the electrode D4 of thelowermost pair. Preferably the electrodes D, D5, and D4 are the positiveelectrodes, while the electrodes D', D2, and D5 are the negativeelectrodes, and the construction above described is such that thematerial in its descent through the furnace passes closer to thepositive electrode of each pair than the negative electrode thereof, andthereby receives the most effective heat of the arcs.

In conjunction with the means herein described for momentarilyretardingorarresting the progress of the material in the effective areasof the arcs I have provided means for elongating or deecting the arcsbetween the two upper pairs of electrodes toward said ledges A5 A5,whereby the material passing through the arcs will not only be subjecteda greater length of time to the heat of the arcs, but said arcs act toheat said ledges A5 A, which in turn give off their heat to moreeffectively fuse said material. The means for elongating or dei'lectingthe arcs in the manner described consists of magnets E E', the former ofwhich extends through the wall of the furnace and has its inner endlocated closely adjacent to the ledge A5, while the latter occupies alike position with respect to the ledge A5. Said magnets are hereinshown as barelectromagnets; but it will be understood thathorseshoe-magnets may and desirably will in practice be employed andthat I may employ either electromagnets or permanent magnets. I prefer,however, to use for this purpose the electromagnets for the reason thatI am enabled thereby to vary the strength of the magnets, and thereforeaC- curately adjust the same to the strength of the current used to formthe arcs between said electrodes.

In order to localize to an extent the fields of force of the magnets, sothat said magnets will act effectively upon the arcs of their associatedelectrodes D D and D2 D3, respectively, metal plates F F are embedded inthe walls of the furnace between said magnets and the subjacentelectrodes of the other pairs. The plates F F' each prevents the linesof force of the magnet above the same from influencing the arcs nextsubjacent said magnets, so that the force of each magnet acts to draw orelongate each arc downwardly toward or upon the ledge next beneath thesame. In practice the magnets associated with each pair of electrodeswill be located such distance from the magnets of the next subjacentpair as to minimize the eect of said magnet upon said latter electrodes.The localization of the fields of force of said magnets is more perfectin the use of horseshoemagnets, and by the employment of ahorseshoe-magnet and the proper use of magnetic metal for diverting orlocalizing the eld of force practically the entire strength of themagnets may be brought to bear to defiect the arcs toward their properledges.

The lower pair of electrodes D4 D5 are situated immediately above theopen-topped Crucible C. The arc formed between said electrodes iselongated or diverted into the Crucible by means of a magnet E2, whichis embedded in the wall of the furnace beneath said Crucible. Saidmagnet, as the others before described,`is herein shown as abarelectromagnet, but may be made of other form, as indicatedhereinbefore. rlhe molten metal is carried off from the Crucible throughthe medium of an inclined spout C', which extends through the wall ofthe furnace and communicates with the Crucible at the upper end thereof.It will be seen, therefore, that the arc formed between the lower pairof electrodes is brought into Contact with or impinges upon the uppersurface of the molten material in the Crucible, so that said material issubjected to the heat of the lower arc as it first passes into theCrucible and thereafter, as the material passes od the top of the moltenmass through the spout C', again brought into contact with or impingedupon by said lower arc.

The Crucible C is adapted to be inserted into place in the furnacethrough an opening A9 in the furnace-wall at one side thereof, as shownin Fig. 3, and through which opening the discharge-spout C of theCrucible extends. Said opening is shown in Fig. 3 as being empty toillustrate the manner of forming the opening; but in practice after theCrucible has been located in the lower end of the furnace said openingis filled with a suitable refractory llling A10, as shown in Fig. 4.

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. to said bars.

When it is desired to remove the crucible and replace the same with aperfect one, the material A10 must first be removed, so as to permit theremoval of the Crucible and the insertion of a new one. The metal shieldsurrounding said furnace is provided with a removable door a, throughwhich the spout C extends, and is provided inside said door with a ringor frame. a', which acts to hold or confine the body of insulatingmaterial A4 in place around said opening.

The electrodes D to D5, respectively, fit snugly in suitable openings inthe furnacewalls and the shield. The shield is provided around theopenings therein through which the electrodes extend withinsulating-rings d2. The magnets are severally seated in suitablerecesses in the walls of the furnace, and the magnets E E extend throughopenings in the shield, and the shield is provided around said openingswith similar insulati n g-rings a3. The electrodes are thrust throughsaid openings in the furnace-wall by the following-described devices.The devices which are associated with each electrode are similar to eachof the other devices, so that the following description of one devicewill serve for all of the other devices.

G designates a yoke the ends of which are inserted in vertical groovedbars I-I H, attached to the side walls of the shield of the furnace, oneon each side of each electrode. Said bars are provided with undercutgrooves, and the arms of the yoke are provided with flanges g, which areof dovetail form in crosssection, as clearly shown in Fig. 4, and whichiit the undercut grooves of the bars and form interlocking connectionswhich prevent separation of said yoke and bars laterally and permit saidyoke to slide vertically with respect G designates a screw-shaft whichhas screw-threaded engagement with an opening in the transverse memberof said yoke and is adapted to exert pressure at its inner end upon theadjacent electrode to force the same inwardly into the furnace. Saidscrew-shaft is provided on its outer end with a hand-wheel G2, by whichthe same may be properly rotated. The screw-shaft G is provided on itsend opposite the wheel G2 with a anged cap G3, adapted to fit over aring G4, which latter surrounds the reduced extension G5 of theelectrode. The shaft G is insulated from the yoke G by a collar G7, ofrubber or other suit-able insulating material, which fits within asuitable aperture in the yoke and which in turn is provided with acentral aperture through which the interiorlyscrew-threaded nut G8 ispassed. The nut G8 is provided with radial ribs or feathers G9, fittingin a suitable recess in the insulating collar GT to prevent the nut G8from turning with the shaft G. The collar G7 is held in position by acentrally-apertured insulating plate G1o and a centrally-aperturedretaining-plate G11 by screws G12 or otherwise. Said ring is connectedin any suitable manner with a circuitwire I and by which said electrodesare brought into circuit with a source of electrical energy. The arms ofthe yoke G are made of considerable length, somewhat greater than thelength of an individual electrode, so that the pressure of thescrewshaft G may be applied to said electrode when the latterisbeinginserted into the opening in the furnace-wall. In this manner theelectrodes are forced inwardly as the inner ends of the same areconsumed. rlhe yokes are supported in said bars at the level of theirassociated electrodes by means of stop-blocks g3 in the grooves of saidbars, which are held in place by set-screws g4, Fig. l, which passthrough said blocks and into said bars. When an electrode is to beinserted into the furnace, the stop-blocks are shifted downwardly andsecured in the lower ends of said bars, the bars being provided at theirlower ends with apertures to receive the set-screws g4, after. which theyoke is slipped downwardly below the level of the electrode. A newelectrode is thereafter inserted in place and the yoke raised to bringthe screw-shaft in position to properly engage the electrode to forcethe same into the furnace. After the yoke is raised the blocks gaare setinto their upper positions to hold the yoke in place.

As a further and separate improvement I propose to so form theelectrodes that they may be fed into the central passage of the furnacecontinuously without the necessity of withdrawing the unconsumedportions of the electrodes from the furnace when supplying newelectrodes. For this purpose the end of each electrode remote from thereduced extension G5 thereof is provided with an axial socket G6, whichis adapted to it over the reduced extension of another or adjacentelectrode, as clearly shown in Fig. 6. Vtith this construction when oneof the electrodes has been forced almost entirely into the opening inthe furnace-wall the ring G4, to which the associated electric wire I isattached, is detached from said electrode, another el'ectrode fittedthereto, thelatter electrode being slipped over the reduced eXtension ofthe partially-consumed electrode, the ring G4 applied to the outer orreduced end of the new electrode, and pressure applied to both of saidelectrodes through the screwshaft G. The inner ends of the firstelectrodes are made solid, as it is not required that they haveinteriitting connection with other electrodes. If desired, theoverlapping ends of the electrodes maybe provided with screw-threads orother interfitting connections, as shown in Figs. 5 and 6, so as to forma connection between said electrodes which will permit the same to bedrawn outwardly as wellas forced inwardly. The rings G4 are similarlyscrewthreaded to engage said reduced extension.

It will be desirable to move said electrodes in both directions when theoperation of the furnace is started, for the reason that the elec- IOOIIC

trodes of each pair should be moved toward each other in firstestablishing the arc and thereafter withdrawn the required distance toproduce the proper length of arc. By the use of the interittingconnection shown I am enabled to manipulate the electrodes in the mannerdescribed.

The means herein shown for feeding the granular material to the furnaceconsists of a horizontal spiral screw J, mounted in a suitable shell J',which is connected at one end with the feed-pipe B of the furnace andatits other end with a hopper J2, through which the materialis fed tothe conveyer-shell. The shaft of the conveyer is provided with a pulleyJ4, which is operated from any suitable source of power through themedium of a belt J5. As a further and separate improvement and one whichis capable of application to other furnaces wherein is employed devicesfor feeding a granular substance tothe furnace the conveyer-shell islocated within a suitable chamber K, which completely incloses the same,and said chamber is connected with the upper end of the furnace throughthe medium of a pipe K. The purpose of said chamber and pipe is todirect the heated gases from the furnace around the shell of theconveyer, so that the granular material passed therethrough will be toan eX- tent heated before it is discharged into the furnace proper. As ameans of more effectively heating said shell the chamber K is divided bya horizontal partition K2 into an upper and lower part, which areconnected by a transverse passage K3 at the end of the chamber remotefrom the entering end K/ of the pipe thereinto, and the other end ofsaid passage communicates with an exit-opening K4, which surrounds thelower end of the hopper J2. The hopper J2 is desirably surrounded by asuitable flaring casing K5, made similar in shape to that of the hopper,so as to confine the gases around said hopper, and thereby transmit amaximum amount of heat to the material on its way to the furnace. Thewalls of the furnace are provided with passages a4 a4, located one atthe side of the electrode D at one side of the furnace and the other atthe side of the electrode D2 at the opposite side of the furnace. Saidpassages are provided to permit the furnacegases to pass upwardlythrough the furnaces without being required to pass through the arcs.

The walls of the furnace adjacent to the walls through which theelectrodes extend are provided with peep holes d5, through which theoperations of the furnace may be observed. Desirably one peep-hole willbe located at the level of each arc and one at the level of each ledgeASA, the former to enable an attendant to properly regulate the aros andthe latter to determine the action of the arcs upon the ledges and toknow the condition of the material which is passing over said ledges.

The furnace herein shown may be used for' smelting or fusing all kindsof materials requiring an intense heat to reduce the same. When thefused or molten material is drawn continuously from the crucible, theoperation of the furnace may be continuous, the granular material beingfed continuously to the furnace and the molten material drawn in in likequantities therefrom. The withdrawal of the molten material from thecrucible may, however, be intermittent, as when in the use of thefurnace in a glass-factory the molten material is withdrawn by the useof pontils. In the latter use of the furnace the crucible may be made ofgreater capacity or may discharge into a refining-crucible, from whichthe molten material is drawn, and the material may be fed to thecrucible in reduced quantities to correspond with the rate ofwithdrawal, or the feed of the material may be intermittently suspended.In the latter event the upper arcs may be discontinued and only thelower arc employed for keeping properly heated the mass of moltenmaterial in the crucible.

In the use of the furnace in a glass-making plant the silica or silicacompound is thoroughly dried during its passage through theconveyer-shell and feed-pipe B and is considerably heated when depositedupon the upper ledge in the passage of the furnace. The material is bysaid ledge momentarily retarded and in such momentary stoppage issubject not only to the heat of the arc above the ledge, which iselongated toward the ledge by the adjacent magnet, but also to theradiated heat of said ledge, the latter being heated to an intensedegree by the impingement of said arc thereagainst. The heated materialdrops from said iirst ledge through the second are upon the secondledge, where its progress is momentarily arrested, and from said ledgethe material, which is at this time in a partially or wholly moltencondition, drops into the crucible C. From the crucible the moltenmaterial passes 0E through the spout C, so that upon leaving thecrucible the molten material is subjected to the highest temperature ofthe adjacentarc, which insures a free-Howing consistency to the moltenmaterial. The length of the interior passage of the furnace and thenumber of ledges therein may be increased or decreased, as foundnecessary or desirable, to produce the required smelting of the materialin its passage therethrough, and a less number than all of said arcsmaybe used at a given time, as found necessary or desirable. Anysuitable means (not shown) may be employed for disposing of the moltenmaterial asit is discharged throughthe pipe C.

Many changes may be made in the structural details Without departingfrom the spirit of my invention, and I do not wish to be limited to suchdetails except as hereinafter made the subject of specific claims.

I claim as my inventionl. In an electric furnace, means for feeding IOOIIO

the material thereto, -means for withdrawing the molten materialtherefrom, electrodes arranged to form an arc through which thematerialis passed, an oblique ledge or wall located in the path of thematerial below said arc against which the materialimpinges after passingthrough said arc, and a magnet for deflecting the arc toward said ledgeor wall.

2. In an electric furnace, means for feeding the material thereto, meansfor withdrawing 'the molten material therefrom, electrodes arranged toform an arc through which the material is passed, and an electromagnetlocated below and adjacent to said are, so as to elongate the arc in thedirection of travel of the material through the furnace.

3. An electric furnace provided with an interior passage, means forfeeding the material to one end of the passage, means for withdrawingthe molten material from-the other end of said passage, electrodesarranged to form an arc in said passage, the wall of the passage beingprovided below said arc with an oblique ledge which extends into thepath of the material, and a magnet embedded in said wall adjacent tosaid ledge.

4. In an electric furnace provided with an interior passage, means forfeeding the material to one end of the passage, means for withdrawingthe molten material from the otherend of said passage, electrodesarranged to form a plurality of arcs in said passage, one in advance ofthe other and through which the material successively passes, the wallof the passage adjacent to each pair of electrodes being inclined,andmeans for elongating the arcs toward the inclined parts of thepassage.

5. An electric furnace provided with an interior passage, means forfeeding the material to said passage, means for withdrawing the moltenmaterial therefrom, electrodes arranged to form a plurality of arcs insaid passage, one in advance of the other, and through which thematerial successively passes, and magnetic means for elongatiug each arcin the direction of travel of the material through the furnace.

6. An electric furnace provided with an interior passage, means forfeeding the material to one end of the passage, means for withdrawingthe molten material from the other end of said passage, electrodesarranged to form a plurality of arcs in said passage, one above theother and through which the material successively passes, means forlaterally elongating each arc, and means located on that side of eacharc toward which it is elongated for momentarily arresting the material.

passage being provided beneath certain of the arcs with oblique ledgesextending into the path of the material and means for elongating saidarc or arcs toward said ledge or ledges.

8. An electric furnace provided with an interior passage, means forfeedingthe material to one end of the passage, means forwith drawing themolten material from the other end of said passage, electrodes arrangedto form a plurality of arcs in said passage, one above the other andthrough which the material successively passes, the wall of said passagebeing provided beneath certain of the arcs with oblique ledges extendinginto the path of the material, and a magnet embedded in the wall of thefurnace adjacent to each ledge or ledges.

9. An electric furnace provided with an interior passage, means forfeeding the material to one end of said passage, a crucible located atthe other end of said passage, electrodes arranged to form a pluralityof arcs in said passage through which the material successively passes,one of said arcs being located immediately above said crucible, andmeans for defiecting said arc into said crucible. e

l0. An electric furnace provided with an interior passage, means forfeeding the material to one end thereof, a Crucible at the lower end ofYthe passage, electrodes arranged to form a plurality of arcs in saidpassage, one above the other, one of said arcs beinglocated immediatelyabove the open end of said crucible, obliqueledges below certain of thearcs and extending into the path of the material,4 magnets in the wallof the furnace adjacent to said ledges and a magnet below said crucible.

1l. An electric furnace provided with an interior passage, means forfeeding the material to the upper end thereof, a Crucible at the lowerend of the passage, electrodes arranged to form a plurality of arcs insaid passage, one above the other, one of said arcs being locatedimmediately above the open end of said crucible, oblique ledges belowcertain of the arcs extending into the path of the material, magnets inthe wall of the furnace adjacent to the ledges, a magnet below saidcrucible, and a spout communicating with the upper end of said crucibleadjacent to the lower arc for drawing off the molten material therefrom.

l2. An electric furnace provided with acrucible open at its top, meansfor continuously feeding the material thereto, electrodes arranged toform an arc over the open end of said crucible and through which thematerial passes into the crucible, means for continuously withdrawingthe molten material from the crucible, and a magnet located below saidCrucible.

13. A furnace provided with a Crucible open at its top, means forcontinuously feeding the material thereto, electrodes arranged to formIOC IOS

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an arc over the open end of said Crucible and through which the materialpasses into the crucible, a draw-olf spout communicating with the upperend of said Crucible adjacent to said arc, anda magnet located belowsaid Crucible.

14. An electric furnace provided with an interior passage, means forfeeding the'material to the upper end thereof, a Crucible located at thelower ond of the passage, electrodes arranged'to form a plurality ofarcs in said passage,one above the other,one of said arcs beinglocatedimmediatelyabove the open end of said Crucible, oblique ledges locatedbelow certain of the arcs and extending into the path of the material,magnets in the Wall of the furnace adjacent to said ledges, a magnetbelow said Crucible, and means acting to localize the effect of theupper magnets to elongate the adjacent arcs toward said ledges.

15. An electric furnace provided With an interior passage, electrodesarranged to form a plurality of arcs in said passage through which thematerial successively passes, magnets in the wall of the furnace andassociated with certain of the electrodes for laterally deflecting thearcs, and metal plates in the wall of the furnace between each of saidmagnets and the unrelated electrodes adjacent thereto.

16. An electric furnace provided with an interior passage, means forfeeding the material to the upper end thereof, a Crucible at theV lowerend of the passage, electrodes arranged to form a plurality of arcs insaid passage, one above the other, one of said arcs being locatedimmediately above the open end of said crucible, oblique ledges belowcertain of the arcs exteudinginto the path of the material, magnets inthe wall of the furnace adjacent to said ledges, a magnet below 'intotwo communicating parts, one of which communicates with said pipe andthe other with an exit-opening.

18. An electric furnace provided with a passage, means for feeding thematerial to said passage, means for withdrawing the material therefrom,electrodes arranged to form an arc in said passage through which thematerial is passed and means located at the outside of the furnace'forcontinuously feeding said electrodes to said passage as they areconsumed, comprising yokes connected with the Walls of the furnace androtative shafts having screw-threaded engagement with the yokes andadapted for connection at their inner ends with the electrodes, andmeans for raising and lowering said yokes on the Walls of the furnace topermit new electrodes to beinserted into the openings in said furnacewhich receive the electrodes.

In testimony that l claim the foregoing as my invention I affix mysignature, in presence of two witnesses, this 24th day of December, AfD.1901.

ALBERT A. SHADE.

Witnesses:

TAYLOR E. BROWN, C. CLARENCE PooLE.

